Water-cooled furnace



' 2 sheets-sheet 1 G. A. REHM WATER-COOLED FURNACE Oct. 17, 1950 FiledAug. 8, 1947 oct. 17, 195o G. A, REHM 2,526,416

WATER-(zoomen FURNACE Filed Aug. 8, 1947 2 sheets-sheet 2 @www PatentedOct. 17, 1950 In"WATER-#C0OLED EURNACE I.'@tust-av.ArRehm,eWorcesteir,Mass., `assigner to 1. Rileytoker f Corporation, 'Worcesterj- Mass., a

corporation of'Massachusetts i Application vAugust 8,1947,.,,Seriailotfl This invention relates towater cooled furnaces,

i and more particularly to the construction and arrangement of hopperbottom furnaces forrthe combustion of pulverized coal orsimilar fuels insuspension.

It has been proposed heretoforerto construct the lower portion of afurnaceV in the form of a V in longitudinal cross section, the front andrear walls of the furnace -bottom converging downwardly toward atransverse slot or opening through which thefuel ash is discharged. The

y side walls of such furnaces are usually provided With upright waterwall tubes,.but in general it .has not been considered feasible toextend these i tubes downwardlyinto the Vrshaped portion of the.furnace, primarily because of the` difculties involved in supplyingwater. to the tubes. Consequently, the side walls ofthe hopper bottomv1. have ordinarily been constructed ofbrickwork Without water cooling,Aand this has resulted in excessive air infiltration and.highmaintenance l walls thereof.

It is a further object of the invention to prov vide a hopper bottomfurnace in which the side walls of the main combustion chamber, as wellas the side walls of ther hopper bottom, are adequately cooled by watertubes.

It is a further object of the invention to provide, a simple andrelatively inexpensive construction for a hopper bottom furnace, inwhich the side walls are cooled by `water vtubes and the need forbrickwork is avoided.

It is a further object of the invention` to provide a hopper bottomfurnace having a new and advantageous arrangementv of Water tubes forcooling the various Walls, and a highly effective downcomer system forsupplying water to the tubes.

With these and other objects in view, as will be apparent to thoseskilled inthe art, the invention resides in the combination of parts setforth in the specification and covered by the claims appended hereto.

Referring to the drawings illustrating one embodiment of the invention',and in which like reference numerals indicate like parts,

Fig. 1 is a longitudinal sectional view of the lower portion of a watercooled furnace, the section being taken on thek line I-I of -Fig. 2;

Fig. 2 is a section taken on the line 2-2 of 4Fig; 3` is al sectiontaken on the line 3-3' of j Fig. l and Figl Il;A is a fragmentary planView taken as L `indicated by the line lei-li of Fig. 1.

5 f They embodiment illustrated comprises a furnace or combustionchamberj It having a front "wall II, a rearwall I2, and two side walls'I4, th'efront Wall having'an opening" I5 therein vfor Vtheintroduction"of a suitable fuel, such as m pulverized coal, which is burned insuspension. f- 'At the rear ofthe combustion' chamber there is f`mounted a `transverse horizontal water drum I6 from which a bank ofconvection water tubes f I8"ert e'nds=rv upwardly. An` upright b'aliefiiis 1"5'mounted'at' the front`of thetube banlrl to deflect" the" furnacegases upwardly in a wellknown mannerf''he usual soothopper '2Q isff-provided behind the drum? Ii to collect particles of soot orfash'-which may be carried rearwardly 20" over'- the top ofthe bale i9.

The lower vp'ortion'of the combustion chamber Il) is shaped tof'providea hoppe'rbottomwhich will' collect anddi'scl1argev the`ash^which isdeposite'dftherein)from the `burning fuel'.` lFor this 25 purpose areawb'ottomwall 22 slopes ldownwardly and `forvl/'ardlyf'from'therloweri marginof the "rear wall i2,'and afrontbottom wallt slopesdownwardly and rearwardlyV fromthe lower marginiof' thevfront'w'alliIf'Th'e lower portions gf, 'of the'sloping w'alls'22VV and 23k areseparated by a comparatively..narrowY "transverse slot '24through'whiclrthe"ashes maydrop into an ash pit 26 therebeneath-Theselsloping'vvallsextend between th'e'sideiwalls'A IQ." An'access ldooropenrg' ing 2l' is provided inone" of'the'side walls, somea what abovetheslotZt.

G'The: upper surface of the sloping rear iwall i? 22of the hopper isiprotected fand" cooledv by 4rrsmeans'of a'row.' of inclined water tubes29 which de: are connectedat their-lower ends to a transverse'fhorizontal header" 3i] located adjacent to 4the :.f-f-lowerfedgeof'rthe Wall; ;These;tubes extend up- 1: wardly valong-.the rear wallVI2 :and thebaille I9. )TeInf orderthat'-A an adequate supply of rwater.may Is-be deliveredto. the vheadert;Y this header is connected to thewater drul'nf.v It by. means of a '.:trowofrtdowncemerl tubes 3i:located. slightly to the-rear of the .tubes 2 9. ffihe upper surfaceofthe? sloping front wall 50-` 23 of the hopper is protectedand cooled bymeans ofv a `rowi of inclined-.water tube'sl 'whichv are'nconnectedattheir lower'A ends -to a v transverse .-'rrzhorizontalheader 3%. located adjacent thexlower edge of thefrwalh fThesetubes'extendvupwardly halon'gfthe ffrontwialli II.`1 lnworderthat: anadefxquatersupply of vwaters'mayY be deliveredto the header 34, its endsare connected to the adjacent ends of the rear header 30 by means ofhorizontal headers 35. It will be apparent that the headers 3B and 34,in conjunction with the two headers 35, form a header structure ofgenerally rectangular shape which surrounds the ash discharge slot 24.

Provision is made for protecting and cooling the side walls I 4. Forthis purpose a row of spaced water tubes 31 is provided adjacent eachside wall. The lower ends of the tubes I31 are connected to the headers35. and the tubes extend upwardly along the inner surfaces of the sidewalls l ll. These tubes are relatively few in number and comparativelywidely spaced, but they are sufficient for the protection of the lowerportions of the side walls of the hopper, which are not subjected tovery high temperatures in service. Certain of these tubes are bentlaterally to avoid interference with the door opening 21. The upperportions of the side walls I4 require additional protection, andaccordingly other upright water tubes 3B are arranged to extend alongthe inner surfaces of these walls. The lower ends of the tubes 3Badjacent each wall are connected to a horizontal header 39 which islocated an appreciable distance above the corresponding header 35 butpreferably somewhat below the tops of the sloping walls 22 and 23. Eachheader 39 is positioned at the outer side of the corresponding group ofwater tubes 31. 'Ihe tubes 38 are preferably located in a common planewith the tubes 31, except for the end portions of the tubes. which arebent to enter the headers. As best shown in Fig. l, the tubes 38adjacent to the -central portion of each side wall are widely spaced andalternate with the tubes 31, whereas the tubes 38 adjacent the front andrear portions of the wall are closely spaced. Thus the portion of thewall above the header 39 is protected throughout by closely spaced tubescertain of which extend downwardly to protect the lower portion of theside wall of the hopper.

The headers 39 are adequately supplied with water by an independentdowncomer system. For this purpose these headers `are extendedrearwardlv, and a row of tubes 4I connects the drum I5 with the rearportions of the headers. The tubes M are located behind the tubes 3|,and they are bent laterally (as best shown in Fig. 4) to connect withthe headers.

The operation of the invention will now be apparent from the abovedisclosure. The water tubes 29, 33, 31 and 3S will absorb heat which isradiated from the combustion flame, and some of the water in these tubeswill be changed to steam. This will produce an upward flow of the steamand water mixture in these tubes. Water will ow downwardly through thetubes 3l from the drum I6 to the rear header 30, and thence forwardlythrough the lower side headers 35 to the front header 34. Thus the lowerends of the tubes 29, 33 and 31 will be supplied with water. Water willalso flow from the drum I6 downwardly through the tubes 4| to the rearportions of the upper side wall headers 39 and thence forwardly throughthese headers, thereby supplying water to the lower ends of the tubes38. Thus an adequate supply of water will be provided for all of theheat exposed tubes, a rapid circulation will be ensured, and there willbe no possibility of a reverse iiow in any of the tubes.

The construction is comparatively simple and inexpensive. The side wallsof the hopper bottom are eiectively water cooled, and no brickwork isrequired in their construction.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

l. A water cooled furnace comprising two opposed upright side walls, twoopposed sloping bottom walls extending between the side walls andconverging downwardly toward an ash discharge opening, a substantiallyhorizontal lower header located adjacent the lower margin of each sidewall, water wall tubes extending upwardly from each of said headers, asubstantially horizontal upper header located an appreciable distanceabove each lower header and at the outer side of the corresponding waterwall tubes, other Water wall tubes extending upwardly from each of saidupper headers, and downcomer means to supply water to all of saidheaders.

2. A water cooled furnace comprising two opposed upright side walls, twoopposed sloping bottom walls extending between the side walls andconverging downwardly toward an .ash discharge opening, a substantiallyhorizontal lower header located adjacent the lower margin of each sidewall, a substantially horizontal upper header located an appreciabledistance above each lower header, closely spaced upright water walltubes associated with the side walls above the upper headers, certain ofthe said tubes being connect-ed at their lower ends to the upper headersand other` of the said tubes extending downwardly past the inner sidesof the upper headers to connect at their lower ends with the lowerheaders, and downcorner means to supply water to all of said headers.

3. A water cooled furnace as covered by claim 2, in which one of theside walls is provided with an access door opening located between thecorresponding upper and lower headers, and certain of the downwardlyextending tubes are bent laterally to avoid interference with said dooropening.

4. A water cooled furnace comprising two opposed upright side walls, twoopposed sloping bottom walls extending between the side walls andconverging downwardly toward an ash discharge opening, a substantiallyhorizontal lower header located adjacent to the lower margin of eachside wall, a substantially horizontal upper header located anappreciable distance above each lower header, upright water wall tubessociated with the side walls above the upper headers and connected attheir lower ends to the upper headers, the tubes adjacent to the centralportion of each side wall being spaced apart more widely than the tubesadjacent to the front and rear portions of the side walls, other uprightwater wall tubes located between the said more widely spaced tubes andextending downwardly past the inner sides of the upper headers toconnect at their lower ends with the lower headers, and downcomer meansto supply water to all of said headers.

5. A water cooled furnace comprising two opposed uipright side walls,two opposed sloping bottom walls extending between the side walls andconverging downwardly toward an ash discharge opening, a substantiallyhorizontal lower header located adjacent to the lower margin of eachside wall, a substantially horizontal upper header located anappreciable distance above each lower header, closely spaced uprightwater wall tubes associated with the side walls above the upper headers,alternate tubes adjacent to the central :portion of each side wallextending downwardly past the inner sides of the uppei headers toconnect at their lower ends with the lower headers, the remaining tubesbeing connected at their lower ends to the upper headers, and downcomermeans to supply water to all of said headers. Y

6. A water cooled furnace comprising two opposed upright side Walls, twoopposed sloping bottom walls extending between the side walls andconverging downwardly toward an ash discharge opening, a substantiallyhorizontal lower header located adjacent to the lower margin of eachside wall, a substantially horizontal upper header located anappreciable distance above each lower header, closely spaced uprightwater wall tubes associated with the side walls above the upper headers,certain of the said tubes being connected at their lower ends to theupper headers and other of the said tubes extending downwardly past theinner sides of the upper headers to connect at their lower ends with thelower headers, a substantially horizontal header located adjacent to thelower margin of each of said sloping walls, water tubes extendingupwardly from each of the last-mentioned headers and along theycorresponding sloping wall to cool the same, and downcomer means tosupply water to all of said headers.

7. A water cooled furnace as covered by claim 6, in which the ends ofthe said last-mentioned headers are connected to the ends of the lowerside wall headers to form a header structure of generally rectangularshape surrounding the ash discharge opening. v

8. A water cooled furnace comprising two opposed upright side walls, twoopposed sloping bottom walls extending between the side walls andconverging downwardly toward an ash discharge opening, a substantiallyhorizontal header associated with each side wall and located anappreciabledistance above the ash discharge opening, upright water walltubes associated with the side walls above the headers, certain of thesaid tubes being connected at their lower ends to the headers and otherof the said tubes extending downwardly past the inner sides of theheaders to cool the lower portions of the side walls, downcomer means tosupply water to the headers, and other downcomer means to supply waterto the lower ends of the said downwardly extending tubes.

9. A water cooled furnace comprising two opposed upright side Walls, twoopposed sloping bottom walls extending between the side walls andconverging downwardly toward an ash discharge opening, a substantiallyhorizontal upper header associated with one side Wall and located anappreciable distance above the ash discharge opening, upright water walltubes associated with the said one side wall above the header, certainof the said .tubes being connected at their lower ends to the header andother of the said tubes extending downwardly past the inner side of theupper header to cool the portion of the side wall therebeneath, a lowerheader to which the lower ends of the said downwardly extending tubesare connected, downcomer means to supply water to the upper header, andother downcomer means to supply Water to the lower header.

10. A water cooled furnace comprising two opposed upright side walls,two opposed sloping bottom walls extending between the side walls andconverging downwardly toward an ash discharge opening, a substantiallyhorizontal upper header associated with each side wall and located anappreciable distance above the ash discharge opening, upright water walltubes associated with the side walls above the headers, certain of Vthesaid tubes being connected at their lower ends to the headers and otherof the said tubes extending downwardly past the inner sides of theheaders to cool the lower portions of the side walls, inclined watertubes associated with each of the said bottom walls, lower header meansadjacent to the ash discharge opening, the lower ends of the saiddownwardly extending tubes and of the said inclined tubes beingconnected to the lower header means, downcomer means to supply water tothe upper headers, and other downcomer means to supply water to the saidlower header means.

GUSTAV A. REHM.

REFERENCES CITED The following references are of record'in the le ofthis patent:

UNITED STATES PATENTS

